emphasis

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Special forcefulness of expression that gives importance to something singled out; stress.
• noun Special attention or effort directed toward something.
• noun Prominence given to a syllable, word, or words, as by raising the voice or printing in italic type.

from The Century Dictionary.

• noun In rhet.: Originally, a figure consisting in a significant, pregnant, or suggestive mode of expression, implying (especially in connection with the context or the circumstances under which an oration is delivered) more than would necessarily or ordinarily be meant by the words used.
• noun The mode of delivery appropriate to pregnant or suggestive expression; hence, rhetorical stress; in general, significant stress; special stress or force of voice given to the utterance of a word, succession of words, or part of a word, in order to excite special attention.
• noun Special and significant vigor or force: as, emphasis of gesticulation; in general, significance; distinctiveness.
• noun Synonyms Emphasis, Accent, Stress. Emphasis is generally upon a word, but may be upon a combination of words or a single syllable. Accent is upon a syllable: as, the place of the accent in the word “demonstrate” is not fixed. Stress is a synonym for either emphasis or accent. See inflection.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Rhet.) A particular stress of utterance, or force of voice, given in reading and speaking to one or more words whose signification the speaker intends to impress specially upon his audience.
• noun A peculiar impressiveness of expression or weight of thought; vivid representation, enforcing assent.
• noun a special attention given to, or extra importance attached to, something.
• noun something to which great importance is attached.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Special weight or forcefulness given to something considered important.
• noun Special attention or prominence given to something.
• noun Prominence given to a syllable or words, by raising the voice or printing in italic or underlined type.
• noun typography Related to bold.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun special importance or significance
• noun special and significant stress by means of position or repetition e.g.
• noun the relative prominence of a syllable or musical note (especially with regard to stress or pitch)
• noun intensity or forcefulness of expression